Rainfall, tide, and wave overtopping can together cause inundation in some coastal areas. However, there have been few cases of inundation analysis considering compound flooding due to the difficulty of the interdisciplinary technique. The purpose of this study is to suggest an analysis technique of compound flooding in coastal areas that links flow simulation tools of coasts and watershed. XP-SWMM was used to analyze rainfall–runoff simulation and 2D surface inundation analysis. A coupled model of ADCIRC and SWAN (ADCSWAN) was used for analyzing expected flow, including wave spectrum, tide, and storm surge from the distant ocean, and the FLOW-3D model was used to estimate the flow and wave overtopping in the coastal area. The analysis technique was applied to Marine City located in Busan, the Republic of Korea, where rainfall and wave overtopping occurred simultaneously during typhoons, and the results were reasonable. The study results are meaningful as they can contribute to the improvement of reproducibility of real phenomena of compound flooding in coastal areas through linked application of flow simulation tools of coasts and watershed.

The development of coastal areas is accelerating in Korea, even though flood damage constantly occurs. A special law was recently enacted to manage disasters in relation to high-rise and underground-linked complex buildings, and a system of prior consultation for disaster impact reviews was implemented. However, there is no specific technical scope within the system for inundation analysis. The purpose of this study is to suggest technical considerations to reduce inundation damage to high-rise buildings and underground-linked complex buildings constructed in coastal areas. We reviewed various criteria, guidelines, and prior studies and investigated inundation damage cases in coastal areas. We found that flood damage in coastal areas can be caused by rainfall amounts above the design frequency, poor interior drainage during rising tidal water levels, and the inflow of seawater (wave overtopping) during storm surges or tsunamis. We also analyzed the frequency of rainfall occurrence due to recent climate changes and reviewed the cases of damage caused by tidal water levels and wave overtopping. Finally, we proposed a method of inundation analysis for coastal areas during natural disasters. This method may contribute to a reduction in flooding damage arising alongside the development of coastal areas.